What effect does a dirty windshield have on nighttime driving?

Answer: C — Creates glare from oncoming lights

A dirty windshield can significantly impact nighttime driving by creating glare from oncoming headlights. When a windshield is smeared, dusty, or dirty, it diffuses the light from vehicles' headlights that approach from the opposite direction. This scattering of light leads to an increased intensity of glare, making it difficult for the driver to see clearly. The overwhelming brightness can lead to reduced visibility, making it harder to judge distances and spot potential hazards on the road. Maintaining a clean windshield is crucial for safety, especially at night when visibility is already compromised by darkness. A clean surface ensures that light passes through without distortion, allowing for better sightlines and reducing the effects of glare. While the other outcomes may sound plausible, they do not represent the primary issue a driver faces with a dirty windshield at night.